SUMMARY (Core B) Core B will provide baseline clinical and imaging biomarker studies and longitudinal evaluations of 490 study participants, of which at least 50% will be Hispanic. These include 100 participants (referred to as Cohort A), originally at the MSMC site of the former NIH-funded Florida ADRC (a USF-MSMC, U of Miami consortium) and 300 new participants (Cohort B). The cognitive diagnosis of 400 subjects in Cohorts A and B, will include Cognitively Normal (CN) (n=100), PreMCI (n= 100), early MCI (eMCI) (n=100), Late MCI (LMCI) (n=50), Mild Alzheimer s Dementia (AD) (n=50). Cohorts A and B together will provide a valuable resource of participants with normal cognition, or various pre-dementia stages of cognitive impairment (very early, early and late) cognitive impairment and mild dementia who will have had longitudinal evaluations for as long as 14 years by 2019. Additionally, 90 participants (Cohort C) with advanced dementia (CDR=3-5), who have consented to autopsy and are enrolled in the State of Florida Brain Bank, will be recruited. At least 50% of Cohort C will be Hispanic with the goal of increasing brain autopsies from the elderly Hispanic ethnic group so as to enrich our tissue banks for research on this under-represented population, recognizing that our emphasis on the earliest stages of dementia, with a large Hispanic cohort, will likely yield low autopsy rates from Cohorts A and B. A census of at least 300 active participants will be maintained by recruiting additional participants in later years to replenish those lost to follow up-with continuing oversampling of PreMCI and MCI subjects to enable the focus of this application to be on the earliest stages of AD. Given the demographics of the population in the Greater Miami area and our previous recruitment efforts we will target a ~50% Hispanic enrollment. The diversity of the participant cohort provides a unique opportunity for evaluating the variables associated with differential clinical presentations and rates of progression of early stages of AD in both the Hispanic and Non-Hispanic populations. Cohort B will be enriched with participants with a family history of dementia, which substantially increases risk for progression to MCI or AD within three years. Three aims are proposed: Aim 1: To identify, recruit, consent and evaluate 400 participants, of which 50% will be Hispanic. Aim 2: Coordinate data collection (including neuropsychological evaluation with standard and novel computerized tests, structural and diffusion-weighted MRI and amyloid imaging), retention, data entry and management with Cores E and C and biological sample collection, storage and analysis with Core D. Aim 3: Enroll, evaluate and follow longitudinally until autopsy, 90 participants (50% Hispanic) with later stages of dementia.